Glove coating and manufacturing process

ABSTRACT

This invention relates to an elastomeric article with improved lubricity and donnablity and reduced stickiness/tackiness. According to the methods of the invention, the internal surface of the elastomeric article is coated with a polyisoprene coating. The coating of the invention is formed from synthetic polyisoprene rubber that may or may not contain minor amounts of other components. The coating is preferably directly bonded to the underlying elastomeric article.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.11/672,705, filed Feb. 8, 2007, now U.S. Pat. No. 8,110,266. Thedisclosure of the prior application is incorporated herein by referencein its entirety.

1. FIELD OF INVENTION

The present invention relates generally to the field of medical andlaboratory tools. More particularly, the invention relates to a coatingcomposition for skin-contacting surfaces of medical and laboratorygloves.

2. BACKGROUND OF THE INVENTION

Medical and laboratory gloves often must be donned rapidly when used toperform time-sensitive medical procedures or laboratory experiments.Therefore, an important characteristic of these elastomeric articles isease of putting the articles on the wearer's hand, or donnability.Additionally, articles such as medical gloves or condoms, for example,are anticipated to be worn by the user for extended periods of time.Because certain elastomeric articles are used with relatively higherfrequency as well as with prolonged duration, important characteristicsof such articles include their physical properties and their comfort ofuse.

A variety of medical gloves, e.g., surgical gloves and examinationgloves, are well known and readily available in the medical field. Thechemical and physical properties of elastomers used in such gloves havebeen researched, and gloves exhibiting desirable properties inaccordance with their usage have been developed. Properties such astensile strength and elongation modulus, as well as coatings andlubricants, which enhance their usage and/or donning characteristics,have been investigated. A variety of elastomeric polymer compositionshave been examined as well, including formulations using natural andsynthetic latex.

The manufacturing process for producing elastomeric articles fromnatural or synthetic rubber latex involves a curing step during whichcrosslinking or vulcanization through sulfur groups occurs between thepolymer units. Conventional processes for making elastomeric articlesfrom natural or synthetic latex typically involve preparing a latexdispersion or emulsion, dipping a former in the shape of the article tobe manufactured into the latex and curing the latex while on the former.Desirable properties of certain elastomeric articles such as tensilestrength are substantially affected by the cross-linking and curingstages of the manufacturing process.

Coating the inner surface of a glove is well-known in the art. U.S. Pat.No. 3,813,695 to Podell teaches coating a hydrophilic hydrogel plasticon the inner surface of a glove. U.S. Pat. No. 4,143,109 to Stockumdiscloses coating the inner surface of a glove with a layer comprisingan elastomeric material having particulate matter randomly distributedthroughout, the particulate matter having a size greater than thethickness of the elastomeric layer so that the particles protrude fromthe surface. In addition, U.S. Pat. No. 4,499,154 to James and U.S. Pat.No. 4,575,476 to Podell teach coating a hydrogel polymer to a rubberarticle to improve the dry skin lubricity where the hydrogel polymer isa copolymer of 2-hydroxyethylmethacrylate with methacrylic acid (MAA) orwith 2-ethylhexyl acrylate (EHA) or with both MAA and EHA. U.S. Pat. No.5,088,125 to Ansell discloses coating the hand contacting surface of aglove with an elastomeric material comprising a blend of an ionicpolyurethane and a second particulate polymer having particle sizegreater than that of the ionic polyurethane which results in the surfacehaving a cluster of particles on it. U.S. Pat. No. 5,284,607 to Chenteaches coating an elastomer surface with an antiblocking compositionwith particles distributed throughout, the majority of the particleshaving a size greater than the thickness of the antiblocking compositionlayer so that the particles form protrusions on the surface. U.S. Pat.Nos. 5,405,666 and 5,395,666 to Brindle teach coating an elastomericarticle with a dry slip conferring coating which comprises a binder (apolymer with specific properties) and substantially nonaggregatedmicroparticles (silica) of about 4 to about 20 micrometers such that themicroparticles are enveloped by the binder but are partially protrudingtherefrom thus imparting to the surface a microroughened appearance.Finally, U.S. Pat. Nos. 6,391,409 and 6,673,404 to Yeh teach coating anatural rubber or synthetic elastomer glove on the skin-contactingsurface with a cross-linked nitrile rubber blended with a silicone.Interposed between the nitrile rubber coating and the elastomeric gloveis an intermediate layer of a rubber blend comprised of natural orsynthetic rubber and nitrile rubber.

There exists a need in the medical device field for elastomericarticles, especially gloves, with improved donnability while maintainingthe desirable properties found in the natural rubber counterpart,including a comfortable feel.

3. SUMMARY OF THE INVENTION

The present invention is based on the surprising discovery that apolyisoprene coated elastomeric article has physical properties (e.g.,donnability, comfort, feel, surface stickiness) that are substantiallyimproved when compared to an uncoated elastomeric article. This is trueeven when the polyisoprene is compared with materials that are veryclosely related chemically (e.g., natural rubber). Without being boundby mechanism, the improved characteristics are at least in part due tothe chain flexibility of the polyisoprene segment.

The present invention provides for an elastomeric article having acoating formed from polyisoprene bonded thereto so as to provide animproved softness and donnability of the coated surface and reduce thestickiness/tackiness of the coated surface. Additionally, the inventionprovides for a rubber article having a coating formed from syntheticpolyisoprene bonded thereto and treated with a lubricant solution on thecoated surface of the article so as to provide an even further improvedlubricity of the coated surface in both dry and wet donning conditions.The coated elastomeric product of the invention have a softer and morecomfortable feel than an uncoated counterpart.

The invention also provides for a rubber article made from naturalrubber, polyisoprene, polychloroprene, nitrile, carboxylatedacrylonitrile butadiene rubber, styrene butadiene rubber, butadieneco-polymer, polyurethane or mixtures of these rubbers and vinyl. Thesynthetic polyisoprene rubber latex used for coating may contain a minoramount of natural rubber, polychloroprene latex, nitrile latex,carboxylated acrylonitrile butadiene rubber latex, styrene butadienerubber, butadiene co-polymer or polyurethane latex or polyvinyl chloride(vinyl) latex.

The invention provides for a process of making an elastomeric articlewith a synthetic elastomeric polyisoprene coating.

4. BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A-1B show scanning electron micrographs taken on a natural rubberglove with no coating (A) without stretching or (B) after stretching300% for 1 minute.

FIGS. 2A-2B show scanning electron micrographs taken on a natural rubberglove with a polyisoprene coating (A) without stretching or (B) afterstretching 300% for 1 minute.

FIGS. 3A-3B show scanning electron micrographs taken on a natural rubberglove with an acrylic coating (A) without stretching or (B) afterstretching 300% for 1 minute.

FIGS. 4A-4B show scanning electron micrographs taken on a natural rubberglove with a hydrogel coating (A) without stretching or (B) afterstretching 300% for 1 minute.

5. DETAILED DESCRIPTION OF THE INVENTION

The object of the present invention is to provide a coating for the skincontacting surface of elastomeric articles that improves the lubricityand donnability of the article. The coating of the invention is formedfrom polyisoprene rubber latex that may or may not contain minor amountsof other components. The coating is preferably directly bonded to theunderlying elastomeric article. The entire skin contacting surface maybe coated with the polyisoprene coating of the invention or some portionthereof may be coated.

5.1 Elastomeric Article

A variety of elastomeric articles can be made in accordance with theinvention. Such elastomeric articles include, but are not limited to,medical gloves, medical tubes, condoms, probe covers (e.g., forultrasonic or transducer probes), dental dams, finger cots, catheters,films, shunts, valves, stents, implants, and the like. Any elastomericarticle that would benefit from an improved lubricity of the coatedsurface and reduced stickiness/tackiness of the coated surface can bemade using the methods of the invention since the invention providesnumerous advantages and benefits in a number of ways with respect todonning. In preferred embodiments, donnable elastomeric articlescomprise the coating of the invention. In more preferred embodiment,medical gloves comprise the coating of the invention.

In embodiments where the external surface of the elastomeric articlecomes into contact with the skin (e.g., catheter), the polyisoprenecoating is on the external surface of the article.

The underlying elastomeric article can be made of any elastomericcomposition, including but not limited to, polyisoprene, natural rubber,polychloroprene, nitrile, carboxylated acrylonitrile butadiene rubber,styrene butadiene rubber, butadiene co-polymer, polyurethane, vinyl ormixtures thereof. Additionally, in some embodiments, the elastomericarticle can comprise a blend of a natural rubber material with at leastone additional non-natural rubber glove material. Suitable examples ofnon-natural rubber glove materials include, but are not limited to,vinyl, nitrile, polyurethane, neoprene (polychloroprene), styrenebutadiene rubber, butadiene co-polymer and combinations thereof. Inpreferred embodiments, the elastomeric article comprises polyisoprene,natural rubber, and/or neoprene.

In embodiments where the underlying elastomeric article is made ofpolyisoprene, the polyisoprene composition comprises the acceleratorcomposition disclosed in U.S. Patent Publication No. 2004/0169317 (thecontents of which are incorporated by reference in their entirety) toincrease the rate of vulcanization of the polyisoprene.

5.2 Polyisoprene Coating

Any known polyisoprene latex composition can be used in the method ofthe invention to coat the surface of the elastomeric article includingpolyisoprene latex from natural sources (e.g., natural rubber,Guttapercha rubber, and Guayle rubber) and synthetic sources (e.g.,water based latex or non-water based resin). The polyisoprene latex canbe formulated or non-formulated. Polyisoprene latex is the majorcomponent of the coating composition. In preferred embodiments, thecoating is greater than about 50%, about 60%, about 70%, about 75%,about 80%, about 85%, about 90%, about 95%, about 98%, or about 99%polyisoprene latex. Suitable polyisoprene latex which can be used isreadily available and can be obtained from a number of commercialsources, including but not limited to, Kraton IR available from Kraton™Corporation (Houston, Tex.).; Shell International Corporation (Houston,Tex.); Isolex available from Medline Industries, Inc. (Mundelein, Ill.);Aqualast™ E0501 available from Lord Corporation (Erie, Pa.); Purformaavailable from Goodyear (Akron, Ohio), and LIR-700 latex available fromKuraray (Japan). In addition to polyisoprene homopolymers its analoguesand derivatives (such as isoprene containing random copolymers, graftingcopolymers, cyclized copolymers, chlorinated polyisoprene, hydrogenatedpolyisoprene, epoxidized polyisoprene, and starcopolymer (dendrimer)),polyisoprene co-polymers and polyisoprene blends can be used as well.Polyisoprene co-polymers which can be used include any co-polymer havingan isoprene monomer unit and having sufficiently similar chemicalstructural and properties of polyisoprene to exhibit the desirableproperties of the polyisoprene coating. Suitable polyisoprene blends caninclude, but are not limited to: natural rubber; polydiene and itsco-polymers, such as polybutadiene, styrene butadiene rubber, butadieneco-polymer, substituted polydiene, such as polychloroprene;thermoplastic materials, such as polyurethane; vinyl, nitrile and thelike. Combinations of the aforementioned natural rubber and non-naturalrubber materials can also be used in conjunction with the polyisoprenelatex. As used herein, the term “polyisoprene coating” refers to acoating on a skin contacting surface of an elastomeric article that isgreater than about 50% polyisoprene latex.

In one embodiment, no accelerator or cross-linker is used in applyingthe polyisoprene coating. In another embodiment, an accelerator orcross-linker is used in applying the polyisoprene coating. In suchembodiments, any accelerator or cross-linker known in the art can beused to manufacture the polyisoprene latex composition used to coat theelastomeric articles. In a specific embodiment, the polyisoprene latexcomposition used to coat the elastomeric articles comprises theaccelerator composition disclosed in U.S. Patent Publication No.2004/0169317 (the contents of which are incorporated by reference intheir entirety) to increase the rate of vulcanization of thepolyisoprene. More than one accelerator can be used. In a specificembodiment, ZDEC, ZMBT, and DPG can be used together as an accelerator(see U.S. Pat. No. 6,828,387 incorporated by reference in its entirety).

As used herein, the term “coating” refers to a thin film of polyisopreneapplied to the underlying elastomeric article. In one embodiment, such acoating has a thickness that is at least 10× less than the thickness ofthe layer of material making up the underlying elastomeric article. Inanother embodiment, such a coating has a thickness that is at least 100×less than the thickness of the layer of material making up theunderlying elastomeric article. Additionally, the polyisoprene coatingalters the surface properties of the elastomeric article and may or maynot provide a barrier function. The polyisoprene coating of theinvention is distinguished from a polyisoprene “layer”. Such a layerwould be substantially the same thickness as the layer of materialmaking up the underlying elastomeric article. Additionally, apolyisoprene layer would provide a barrier function. The polyisoprenecoating on the elastomeric article can be any thickness that is at least10× thinner than the layer of material making up the elastomeric articleproviding that the coating imparts improved lubricity of the coatedsurface and reduced stickiness/tackiness of the coated surface ascompared to non-coated surfaces. In one embodiment, the polyisoprenecoating is about 1 to about 20 microns, preferably about 5 to about 15microns, and more preferably either about 8 to about 12 microns or about5 to about 7 microns in thickness. The total solids content of thepolyisoprene composition used for coating can be about 0.5% to about15%, preferably about 5% to about 8% depending on the thickness of thecoating desired.

5.3 Manufacture of Coated Articles of the Invention

The underlying elastomeric article can be made by any method known inthe art. Once manufactured, the polyisoprene coating can be applied tothe internal surface of the elastomeric article using any method knownin the art. Preferred embodiments are disclosed infra.

5.3.1 Manufacture of Elastomeric Article

Porcelain molds (or formers) are cleaned thoroughly, e.g., by one ormore of the following steps: (a) mechanically brushing with nylonbrushes, (b) dipping into acid solution e.g. citric acid or nitric acidwhich dissolves residual calcium carbonate powder from the coagulant,(c) mechanically brushing with nylon brushes, (d) dipping into alkalinesolution, (e) mechanically brushing with nylon brushes, and (f) dippinginto hot water (about 50° C. to about 70° C.) which heat them up toabout 60° C. The cleaned molds are dried, e.g., by blowing air onto themand/or placing them into a hot air oven and heating them to about 57° C.to about 61° C.

The cleaned molds are dipped into a coagulant solution (e.g., calciumnitrate and calcium chloride). In embodiments where the coagulantsolution is calcium nitrate, the solution is preferably between about52° C. to about 59° C. with a specific gravity about 1.100 to about1.200 (depending on the thickness of the material required). Thecoagulant solution additionally comprises a mold release agent (e.g.,calcium carbonate and magnesium carbonate) and a wetting agent (e.g.,Surfynol TG and non-ionic surfactants such as Teric 320 and TritonX100). The coagulant-coated molds are dried in an oven (about 100° C.for about 15 seconds) and then dipped into a compounded latex containinga crosslinking agent (e.g., sulfur and a sulfur donor such astetramethyl thiuram disulfide (TMTD) and tetraethyl thiuram disulfide(TETD)), a vulcanizing accelerator (e.g., zinc dibutyldithiocarbamate(ZDBC), zinc diethyldithiocarbamate (ZDEC), zinc mercaptobenzthiazole(ZMBT), and diphenyl guanidine (DPG)), an activator (e.g., zinc oxideand magnesium oxide), an antioxidant (e.g., Wingstay L and Vulcanox BKF)and, optionally, coloring pigment. The dwell time in the latex is about10 seconds and the total solids content of the latex varies from about30% to about 49% depending on thickness required and particularmaterials used. The latex-coated molds are then passed through one ormore, preferably two, hot air ovens to gel the latex film. In oneembodiment, water soluble materials (e.g. calcium nitrate, proteins andsurfactants) are leached out of the film prior to coating withpolyisoprene. In such embodiments, the films are leached in hot water(about 65° C. to about 85° C., preferably in more than one tank, morepreferably in five different tanks) for a total of about 4 minutes. Inanother embodiment, the polyisoprene coating is applied to the filmprior to the leaching step (see Section 5.3.2).

In embodiments that the elastomeric article is made of polyisoprene, themanufacturing process described in U.S. Pat. No. 6,828,387 can be used.

5.3.2 Application of Polyisoprene Coating

The polyisoprene coating of the invention can be applied to anelastomeric article by any method known in the art including, but notlimited to, dipping, spraying, brushing, flowing, and printing. Inpreferred embodiments, the polyisoprene coating is applied by singledipping or multiple dipping. Additionally, the polyisoprene coating maybe applied to the elastomeric article either prior to or after theleaching step.

In a specific embodiment, the polyisoprene coating is applied by thedipping method.

In more specific embodiments where the polyisoprene coating is appliedto the elastomeric article after the leaching step, the leached filmsare dipped into a polyisoprene latex compound.

In more specific embodiments where the polyisoprene coating is appliedto the elastomeric article prior to the leaching step, the latex-coatedmolds are dipped into the polyisoprene latex composition after drying inthe first hot air oven. The molds are then dried in a second hot airoven to gel the latex film. The gelled films are then leached in hotwater as described in Section 5.3.1.

After the elastomeric article is coated with the polyisoprene coating,the elastomer and polyisoprene film-coated molds then go into a seriesof hot air ovens with increasing temperatures from about 115° C. toabout 135° C. for about 20 minutes. In the ovens, the elastomericarticles are initially dried and then vulcanized (i.e., the rubbermolecules are crosslinked by, e.g., sulfur linkages). The curedelastomeric articles are further leached in hot water and then dippedinto a slurry of one or more materials (e.g., calcium carbonate powderor starch powder alone or together and with or without siliconeemulsion) that function as a stripping aid and decreases the stickinessof the elastomeric article. After cooling, the elastomeric articles aremanually stripped from the molds whereby they are turned inside out thusputting the polyisoprene coating on the inside.

The polyisoprene coating composition can optionally contain curingagents to crosslink the polyisoprene molecules including, but notlimited to, sulfur crosslinking system, peroxide crosslinking system(peroxide, hydroperoxide) or prevulcanized/precured polyisoprenemolecules with gamma irradiation. Preferably sulfur crosslinking isused. In such embodiments, the crosslinking agents comprise sulfur,vulcanization accelerators, zinc oxide, and an antioxidant. In specificembodiments, the polyisoprene molecules are bonded directly to therubber surface of the underlying elastomeric article during thecrosslinking reaction.

In one embodiment, there is a single coating of polyisoprene applied tothe elastomeric article. In other embodiments, more than one coating ofpolyisoprene is applied to the elastomeric article. In such embodiments,each of the coatings can be identical in composition or they can vary.Additionally, each of the coatings can be of the same thickness or theycan vary.

5.3.3 Chlorination

The elastomeric articles of the invention can be post-processed bychlorination which removes powder from the elastomeric article andmodifies the internal surface to improve donning and also reduces thegrip on the external surface. The formed articles are turned inside outso that the polyisoprene-coated internal surface is on the outsideexposed directly to the chlorination. The articles are then loaded intoa chlorinator and chlorinated in an aqueous solution of chlorine at achlorine strength of about 400 ppm to about 700 ppm. At the end of thechlorination cycle, any residual chlorine is neutralized by addition ofcaustic soda solution such that the pH of the neutralized solution isabout 8 and above.

5.3.4 Lubrication

In some embodiments, the elastomeric articles of the invention canfurther be lubricated after the chlorination process. Lubrication ispreferred in order to further improve the ease of donning theelastomeric article of the invention, especially donning of the articleson moist surfaces (damp donning). Any method of lubrication can be used.In one embodiment, the coated elastomeric articles are tumbled with anaqueous solution of the lubricant prior to drying. Any type of lubricantcan be used including, but not limited to, a silicone emulsion, acationic surfactant and with or without an anionic surfactant. In apreferred embodiment, the lubricant comprises cetyl pyridium chloride,silicone SM2140 emulsion and ammonium salt of alkyl phosphate (see,e.g., U.S. patent application Ser. No. 10/666,650).

5.4 Characteristics of the Polyisoprene Coating of the Invention

The polyisoprene coating of the invention displays characteristics thatimprove the lubricity and reduce the stickiness/tackiness of the coatedsurface of the elastomeric article.

5.4.1 Soft and Comfortable Feel

The polyisoprene coating of the invention provides a softer and morecomfortable feel than uncoated elastomeric articles. This correlateswith the modulus values of the coated and uncoated elastomeric articles.Those elastomeric articles with lower modulus values feel morecomfortable and softer when donned (see Section 6.9). Polyisoprenecoated natural rubber gloves approximated the feel and softness ofgloves made entirely from polyisoprene (see Table 6, Sample 2A andSample 6).

Additionally, the polyisoprene coating of the invention decreases thestickiness of the coated surface of the elastomeric article as comparedto an uncoated article (see Section 6.8). Comparison of uncoated naturalrubber gloves with polyisoprene coated natural gloves showed asubstantial difference in internal stickiness (see Table 5).

Furthermore, the polyisoprene coating of the invention decreases skinirritation from the coated elastomeric article as compared to anuncoated natural rubber article or an article coated with naturalrubber.

These characteristics are surprising considering that polyisoprene andnatural rubber are very similar chemically. Natural rubber containsabout 98% cis-1,4-polyisoprene whilst synthetic polyisoprene containsabout 90%-98% cis-1,4-polyisoprene depending on the source of thematerial and the method of manufacture (P. Henderson, From “IsopreneMonomer to Synthetic Polyisoprene Latex”, International LatexConference, Jul. 25-26, 2000, Akron, Ohio and F. B. Chen, SyntheticPolyisoprene Latex, 3^(rd) International Rubber Glove Conference &Exhibition, 12-14 Sep. 2006, Kuala Lumpur, Malaysia).

5.4.2 Rough Surface

Polyisoprene coatings of the invention do not provide a flat surface.Rather, the surface is covered with protrusions of various sizes andshapes extending from the surface. The protrusions measure from aboutone half micrometer to several micrometers. The protrusions are composedexclusively of the polyisoprene coating material. No additionalparticles are added to cause the protrusions.

The characteristic of the protrusions can be varied by varying thecomposition and/or deposition method of the polyisoprene coating.

The protrusions can be seen using a scanning electron microscope at1000× magnification and/or an Atomic Force Microscope

5.4.3 Non-Cracking

The polyisoprene coatings of the invention do not show any substantialcracking either when unstretched or when stretched (e.g., 100%, 300%,500%, etc.). In preferred embodiments, the polyisoprene coating does notshow any cracking. As used herein the terms “cracking” or “crack” meansa fissure in the surface of the coating that may or may not extendthrough the entire thickness of the coating to the underlyingelastomeric article.

In one embodiment, the coating can be inspected for cracking using ascanning electron microscope at 1000× magnification. In anotherembodiment, the coating can be inspected for cracking using physicalmanipulation. In such embodiments, the elastomeric article is stretched(e.g., by 100%, 300%, 500%, etc.) and the coated surface is rubbedrepeatedly (e.g. using a finger). In some embodiments, the glove isrubbed using moderate pressure more than 5 times, less than 10 times,less than 20 times, or less than 100 times. The surface is then examinedvisually for flaking and/or release of a powdery substance which canoptionally be made more visible against a black background (e.g., pieceof paper or cloth). The presence of flaking and/or the powdery substanceindicate the presence of cracking. The polyisoprene coating of theinvention shows less cracking and/or flaking as compared to anelastomeric article having an acrylic or a hydrogel coating.

The following examples further illustrate the advantages of theinvention and should not be construed as limiting the invention to theembodiments depicted therein.

6. EXAMPLES 6.1 Example 1 Preparation of a Polyisoprene Coated Glove

A. Glove Production

Porcelain molds (or formers) were cleaned thoroughly by the followingsteps:

(a) mechanically brushing with nylon brushes,

(b) dipping into acid solution e.g. citric acid or nitric acid whichdissolves residual calcium carbonate powder from the coagulant,

(c) mechanically brushing with nylon brushes,

(d) dipping into alkaline solution, and

(e) mechanically brushing with nylon brushes.

The molds were further cleaned by dipping into hot water (50-70° C.)which heated them to about 60° C. The cleaned molds were dried byblowing air onto them before placing them into a hot air oven whichdried and heated them to 57° C. to 61° C.

The cleaned molds were dipped into calcium nitrate coagulant solution(52-59° C., specific gravity about 1.100-1.200 depending on glovethickness required) which also contained calcium carbonate (mold releaseagent) and Surfynol TG (wetting agent). The coagulant-coated molds weredried in an oven (100° C. for 15 seconds) and then dipped into acompounded natural rubber containing sulfur (crosslinking agent), zincdibutyldithiocarbamate (vulcanization accelerator), zinc oxide(activator) and Winstay L (antioxidant) and coloring pigment. The dwelltime in the latex was about 10 seconds and the total solids content ofthe latex varied from 30-49% depending on glove thickness required. Thelatex-coated molds were then passed through two hot air ovens whichgelled the latex film. After that, beads were formed at the end of thecuff area by mechanically rolling down the end portion of the glove.Then the gloves were leached in hot water (65−85° C., in 5 differenttanks) for a total of about 4 minutes to leach out water solublematerials e.g. calcium nitrate, proteins and surfactants from the film.

B. Polyisoprene Coating Application

The leached films were then coated with a polyisoprene coating bydipping into a polyisoprene latex compounded using the formulation shownin Table 1 and having a total solids content of 3-15% preferably 5-8%.The latex film-coated molds then were placed into a series of hot airovens with increasing temperatures from 115° C. to 135° C. for about 20minutes. In the ovens, the gloves were initially dried and thenvulcanization of the rubber occurred whereby the rubber molecules werecrosslinked by sulfur linkages. The cured gloves were further leached inhot water to extract more water soluble materials and then dipped into aslurry of calcium carbonate powder or starch powder which functioned asstripping aid as well as prevented the gloves from internally stickingtogether after stripping. After cooling down, the gloves were manuallystripped from the molds whereby they were turned inside out with thepolyisoprene coating on the inside.

TABLE 1 Polyisoprene coating formulation Ingredients phr Karton IR-401RP latex 100 Soft Water to dilute latex Sodium caseinate 0.75 Zinc oxidedispersion 0.5 Sulfur dispersion 1.25 Bostex 561 (ZDEC) 0.5 ZMBTdispersion 0.5 Bostex 417 (DPG) 1 Wingstay L 2 Ammonium hydroxide forpH > 10.2 adjustingC. Chlorination

The gloves were post-processed by chlorination. The chlorination processremoved powder from the gloves, modified the glove internal surface toimprove donning and reduced the grip on the external surface. The formedgloves were manually turned inside out so that the polyisoprene-coatedsurface was on the outside. The gloves were then loaded into achlorinator where they were washed by tumbling with water for 3 minutesfor two cycles. The gloves were then chlorinated in an aqueous solutionof chlorine at a chlorine strength of 400 to 700 ppm for 8.3 minutes. Atthe end of the chlorination cycle, any residual chlorine was neutralizedby addition of caustic soda solution such that the pH of the neutralizedsolution was about 8 and above. The gloves were tumbled for 4 minutesbefore the solution was drained off. The gloves were then washed bytumbling with water for five times for three minutes each time.

D. Lubrication

After chlorination, the wet gloves were transferred to a waterextraction machine and excess water was removed by centrifuging. Inorder to improve the donning of the gloves on moist hands (dampdonning), the gloves were coated with a lubricant. The gloves werecoated by loading the gloves into a washer where they were tumbled withan aqueous solution containing cetyl pyridium chloride (1.56%), siliconeSM2140 emulsion (1.5%) and ammonium salt of alkyl phosphate (1.2%).After that, the gloves were dried in a cyclone dryer at about 60° C. for20 minutes. The partially dried gloves were manually turned inside outand dried further in a cyclone dryer at about 60° C. for another 30minutes.

6.2 Example 2 Alternative Coating Method

Alternatively, the polyisoprene coating may be applied to the glovebefore the leaching step. In this case, after the first latex dip anddrying in the first hot air oven, the latex-coated molds are dipped intothe polyisoprene latex composition and then dried in the second hot airoven to gel the latex film. The gelled films are then beaded before theyare leached in hot water. The process continues through vulcanization,post-cure leaching and stripping as described in Section 6.1.

6.3 Example 3 Gloves Used for Testing

A. Natural Rubber Gloves with No Coating

Natural rubber gloves with no coating were prepared as described inSection 6.1 except that the dipping into the polyisoprene latexcomposition was omitted. The specific gravity of the calcium nitratecoagulant was about 1.144 and the total solids content of the naturalrubber was about 47.5%. The gloves produced had a finger thickness ofabout 0.30 mm. The formed gloves were chlorinated according to theprocedure described in Section 6.1 using two different chlorinestrengths viz. about 420 ppm and about 550 ppm. After chlorination, thegloves were dried and packed and then evaluated for various properties.Gloves chlorinated at about 420 ppm and about 550 ppm will be referredto as Sample 1A and Sample 1B respectively.

Gloves chlorinated at about 420 ppm also went through the lubricationprocess described in Section 6.1 and the dried gloves (hereinafterreferred to as Sample 1C) were packed and evaluated.

B. Natural Rubber Gloves with Polyisoprene Coating

Natural rubber gloves with polyisoprene coating were prepared accordingto the procedure described in Section 6.1. The specific gravity of thecalcium nitrate coagulant was about 1.144 and the natural rubber totalsolids content was about 47.5%. The total solids content of thepolyisoprene coating composition was about 8%. The gloves were coatedwith a polyisoprene coating after leaching of the natural rubber film.The gloves produced had a finger thickness of about 0.31 mm. The formedgloves were chlorinated according to the procedure described above. Twochlorination levels were investigated viz, chlorine strength of about420 ppm and about 550 ppm. After chlorination, the gloves were dried,packed and evaluated. Gloves chlorinated at about 420 ppm and about 550ppm will be referred to as Sample 2A and Sample 2B respectively. Gloveschlorinated at about 420 ppm also went through the lubrication processdescribed above. The dried lubricated gloves (hereinafter referred to asSample 2C) were packed and evaluated.

C. Acrylic-Coated Natural Rubber Gloves and Non-Coated Natural RubberGloves

A sample of a powder-free chlorinated acrylic-coated natural rubbergloves (chlorinated at about 350 ppm chlorine strength, hereinafterreferred to as Sample 3) and a sample of the chlorinated non-coatednatural rubber gloves (chlorinated at about 350 ppm chlorine strength;hereinafter referred to as Sample 4) were obtained from the samemanufacturer. The acrylic-coated gloves (Sample 3) had a fingerthickness of about 0.23 mm whilst the non-coated gloves (Sample 4) had afinger thickness of about 0.25 mm. The gloves were evaluated for variousproperties. The gloves may be prepared by a coating process similar tothat described in Section 6.1 but with the polyisoprene latex coatingreplaced by an acrylic coating having a total solids content of about1.5% to about 3.5%.

D. Hydrogel-Coated Natural Rubber Gloves

A commercial sample of a powder-free hydrogel-coated natural rubbergloves having a finger thickness of about 0.29 mm (hereinafter referredto as Sample 5) was obtained and evaluated. The gloves were manufacturedby Regent Medical, Norcross, Ga. (product ref 30475, lot 04D1482, expirydate April 2009) and were sterile powder-free latex surgical gloves witha “Biogel” coating.

E. Polyisoprene Gloves

Polyisoprene gloves were prepared as described in Section 6.1 exceptthat compounded polyisoprene latex, the formulation shown in Table 1,was substituted for the natural rubber and the total solids content ofthe latex was about 31.0%. The specific gravity of the calcium nitratecoagulant was about 1.142. The gloves produced had a finger thickness ofabout 0.28 mm. The formed gloves were chlorinated according to theprocedure described in Section 6.1 at a chlorine strength of about 420ppm. After chlorination, the gloves were dried (hereinafter referred toas Sample 6) and ready for testing.

TABLE 2 Gloves Used for Testing Sample Name Glove Coating Example 1Anatural rubber gloves chlorinated at none 6.2.A about 420 ppm 1B naturalrubber gloves chlorinated at none 6.2.A about 550 ppm 1C natural rubbergloves chlorinated at none 6.2.A about 420 ppm and lubricated 2A naturalrubber gloves chlorinated at polyisoprene 6.2.B about 420 ppm coating 2Bnatural rubber gloves chlorinated at polyisoprene 6.2.B about 550 ppmcoating 2C natural rubber gloves chlorinated at polyisoprene 6.2.B about420 ppm and lubricated coating 3 natural rubber gloves chlorinated atacrylic 6.2.C about 350 ppm 4 natural rubber gloves chlorinated at none6.2.C about 350 ppm 5 natural rubber gloves hydrogel 6.2.D 6polyisoprene gloves chlorinated at none 6.2.E about 420 ppm

6.4 Example 4 Evaluation by Scanning Electron Microscopy

A. Experimental Design

The surface morphology of the internal surface coating of the followingglove samples was examined by scanning electron microscopy at 1000×magnification:

-   -   Sample 1A: Natural rubber glove with no coating (control)    -   Sample 2A: Polyisoprene coating on natural rubber glove    -   Sample 3: Acrylic coating on natural rubber glove    -   Sample 5: Hydrogel coating on natural rubber glove

For each glove sample, scanning electron micrographs were taken on (a) asample without stretching, (b) a sample after stretching about 100% for1 minute and (a) a sample after stretching about 300% for 1 minute.

The scanning electron micrographs of the samples (unstretched andstretched 300%) are shown in FIGS. 1 to 4. Micrographs for samplesstretched at about 100% were similar to those stretched at about 300%and were not shown.

B. Observations

Sample 1A. The surface was essentially quite flat. For the unstretchedsample (FIG. 1A) some fine line cracks were discernible. The severity ofthe cracking was not affected by stretching the sample about 100% orabout 300% (FIG. 1B). Cracking of chlorinated natural rubber surface hasbeen reported before (C. C. Ho and M. C. Khew, International Journal ofAdhesion & Adhesives 19 (1999) 387-398) and the severity of the crackingincreased with the extent of chlorination.

Sample 2A. The most prominent feature of the polyisoprene coating wasthat the surface was not flat (FIG. 2A). The whole surface was coveredwith particles of various sizes and shapes protruding from the surface.Some particles (mainly the smaller ones) appeared to be roughlyspherical whilst others were irregularly shaped. The bigger protrusionsappeared to be made up of aggregates of the smaller particles fusedtogether. The protrusions measured from about half micrometer to severalmicrometers. No surface cracking was evident for all the samples whetherunstretched or after stretching about 300% (FIG. 2B).

Sample 3. The surface morphology of the samples was essentially quiteflat with many cracks such that the surface consists of flakes ofacrylic fitted together like a “jig saw puzzle” (FIG. 3A). Thereappeared to be no difference in the severity of the surface crackingamong the samples that was not stretched or stretched to about 100% orabout 300% (FIG. 3B).

Sample 5. The surface morphology (FIG. 4A) showed some similarity toSample 2A in that the surface had protrusions. However, there appearedto be less protrusions compared to Sample 2A and the protrusionsappeared to have more rounded and smoother surfaces and the sizes of theprotrusions were generally bigger. One significant difference was thatsurface cracks were clearly visible for the unstretched sample as wellas for the stretched samples. Samples stretched about 100% and about300% (FIG. 4B) appeared to have more severe surface cracking than theunstretched sample (FIG. 4A).

Based on the foregoing observations, the polyisoprene coating of theinvention does not show any surface cracking for the unstretched glovesas well as for the stretched gloves compared with the prior art coatingswhich show surface cracks even for the unstretched gloves.

6.5 Example 5 Adhesion of Coating

The adhesion of the polyisoprene coating of the invention, acryliccoating and hydrogel coating to the rubber substrate was evaluated usingtwo samples of each glove type. The finger and palm areas of the glovewere stretched to about 500% and the coated surface was rubbedrepeatedly using the thumb. The coated surface was then visuallyexamined for coating flakes and powdery substance. The adhesion of thecoating was rated qualitatively on a scale of 1 to 5, 1 being the worstcase with the entire coating flaking off the rubber substrate and 5being the best case with no sign of flaking and no visual appearance ofpowdery substance on the surface of the glove. The adhesion of thepolyisoprene coating of the invention was excellent with a rating of(i.e. no flaking or shredding of powder was observed after stretchingthe glove to about 500% and rubbing it repeatedly with the thumb). Theadhesion of the acrylic coating (Sample 3) and hydrogel coating (Sample5) was about the same with a rating of 4. In both cases, some whitishflakes came off the gloves after stretching the glove to about 500% andrubbing repeatedly with the thumb.

The above results for the polyisoprene coating of the inventioncorrelated well with the pictures of the surface coating from scanningelectron microscopy which showed no cracking on the surface for theunstretched sample as well as for the stretched samples. The highultimate elongation of the polyisoprene coating (which was higher thanthat of the natural rubber base glove) could explain why no cracking wasobserved when the glove was stretched to about 500%. It could also beconcluded that bonding of the polyisoprene coating to the natural rubbersubstrate (which is chemically similar i.e. also polyisoprene) was verygood.

As noted earlier, the scanning electron micrographs of both the acryliccoated and hydrogel coated gloves showed surface cracking for theunstretched as well as for the stretched samples. The cracking couldlead to delamination of the coating which appeared as flaking of thecoating from the substrate.

6.6 Example 6 Donning of Unlubricated Gloves

Gloves without lubricant were donned by a panel of three researchers whoroutinely work with gloves on dry hands and subjectively assessed forthe ease of donning on a scale of 1 to 5, in which 1 means verydifficult to don and 5 means very easy to don. The results (Table 3)show that compared with uncoated natural rubber glove the polyisoprenecoated glove provides significantly better donning performance. Withoutbeing bound by any particular theory, it is believed that polyisopreneis much more sensitive to chlorination than natural rubber which createsa better textured protrusions on the glove surface resulting in a lowerfriction force during donning.

Additionally, the polyisoprene coating can comply with chlorinationprocess characterized by different chlorine strength, e.g., from 420 ppmto 550 ppm and provides consistent better donnability than uncoatednatural rubber glove.

TABLE 3 Dry Donning of Gloves Glove Sample Dry Donning Rating 2A 4.5 (NRglove, polyisoprene coated) at 420 ppm 1A 1 (NR glove, uncoated) at 420ppm 2B 5 (NR glove, polyisoprene coated) at 550 ppm 1B 2 (NR glove,uncoated) at 550 ppm

6.7 Example 7 Donning of Lubricated Gloves

Gloves treated with lubricant were donned on dry hands as well as onmoist/damp hands and subjectively assessed for ease of donning by apanel of three researchers who routinely work with gloves on a scale of1 to 5, in which 1 means very difficult to don and 5 means very easy todon. The results (Table 4) showed that the polyisoprene coating improvedthe donnability of the gloves (relative to the uncoated gloves) on dryhands as well as on damp hands. Treatment of the uncoated gloves withlubricant improved the donnability of the gloves on damp hands comparedwith on dry hands but the damp donning rating was still significantlypoorer than that of the lubricated polyisoprene coated gloves (Sample2C). Without being bound by any particular theory, it is postulated thatthe higher chlorination efficiency of polyisoprene coating, showed inExample 6 above, can further comply with lubrication process providingbetter damp donning than uncoated natural rubber glove. Accordingly, theuse of lower level ppm of chlorination on the polyisoprene coated glovewill exhibit less surface damage while having the advantages thechlorination treatment.

TABLE 4 Donning of Lubricated Gloves Glove ID Dry Donning Rating DampDonning Rating 2C (polyisoprene 4.5 4.5 coated) 1C (uncoated) 1 2.5

6.8 Example 8 Internal Stickiness

Gloves were packed and sterilized by gamma-radiation at about 29.5 kGyto about 30.3 kGy. The sterilized gloves were aged at about 70° C. for 1day and 7 days and evaluated to assess the extent that the internalsurfaces of the gloves stick to each other, also referred to asblocking. The degree of stickiness was rated on a scale of 1 to 5 with 1representing not sticking at all and 5 representing seriously stickingto each other. Results are shown in Table 5.

The results demonstrate that the inventive polyisoprene coating did notshow any stickiness even after aging for 7 days at about 70° C. comparedwith the uncoated natural rubber surface which showed serious blockingeven after 1 day aging at about 70° C. Without being bound by anyparticular theory, it is postulated that the protrusions on thechlorinated surface of the polyisoprene coating reduces the surface areafor contact and hence reduces the tendency for the surfaces sticking toeach other.

TABLE 5 Internal Stickiness Internal Stickiness Rating Glove ID Aged 70°C./1 day Aged 70° C./7 days Sample 2A (polyisoprene 1 1 coated) Sample1A (uncoated) 4.5 4.5 Sample 2B (polyisoprene 1 1 coated) Sample 1B(uncoated) 4.5 4.5

6.9 Example 9 Physical Properties and Glove Touch Feel

The modulus at different elongation were determined and the resultsshown in Table 6.

Generally, the feeling (after donning) of softness/stiffness of uncoatedrubber gloves of similar thickness may be correlated with the modulusvalues of the rubber e.g. glove with a soft feel would have a lowermodulus than a glove with a stiffer feel. For gloves with a coating, thefeel of the glove after donning would be expected to be governed mainlyby the modulus of the coating material since it is the latter that is indirect contact with the skin.

Sample 3 (acrylic-coated) and Sample 4 (uncoated) gloves were donned andevaluated by a panel of three researchers who routinely work withgloves. The results showed that Sample 3 definitely felt stiffer thanSample 4. In fact, the panel reported that the stiffness of the acryliccoating can be felt by the hands. The feeling of softness/stiffness ofthe gloves actually correlated with the modulus values of the glovesi.e. Sample 3 had higher modulus values than Sample 4. It was notexpected that a thin coating could affect the modulus of the whole gloveunless (1) the modulus of the acrylic coating was very high and/or (2)the coating was not very thin.

Uncoated polyisoprene gloves (Sample 6) and uncoated natural rubbergloves (Sample 1A) were donned and evaluated by the same panel ofpeople. The results showed that uncoated polyisoprene gloves definitelyfelt softer than the uncoated natural rubber gloves. This was expectedand correlated well with the modulus values of the gloves i.e.polyisoprene gloves had significantly lower modulus values than naturalrubber gloves.

Polyisoprene-coated gloves (Sample 2A) and uncoated natural rubbergloves (Sample 1A) were donned and evaluated by the same panel ofpeople. The results showed that polyisoprene-coated gloves were judgedas softer than or similar to uncoated natural rubber gloves. Thiscorrelated well with the modulus values of the two glove samples despitethe fact that the modulus values (M100 and M300) of thepolyisoprene-coated gloves were only slightly lower than those of theuncoated gloves.

M100 % M300 % M500 % Sample ID kg/cm² kg/cm² kg/cm2 Sample 3 13 24 54(acrylic coated) Sample 4 10 18 33 (uncoated) Sample 1A 8 15 33(uncoated) Sample 2A 7 13 28 (polyisoprene coated) Sample 6 5 10 20(Polyisoprene)

6.10 Example 10 Natural Rubber Gloves with an Alternate PolyisopreneCoating

Natural rubber gloves with an alternate polyisoprene coating that wasformulated differently than in Sections 6.1 were prepared in thelaboratory according to the procedure described in Section 6.1. Thecoating composition is given in Table 7. The specific gravity of thecalcium nitrate coagulant was 1.150 and the NR latex total solidscontent was 47.5%. The total solids content of the polyisoprene coatingcomposition was 8%. The gloves were coated with a polyisoprene coatingafter leaching of the NR latex film. The gloves were cured for 30minutes at 135° C. The gloves produced had a finger thickness of 0.30mm. The formed gloves were chlorinated at 420 ppm according to theprocedure described in Section 6.1. After chlorination, the gloves weredried, packed and evaluated.

Gloves were donned on dry hands and subjectively assessed for the easeof donning on a scale of 1 to 5, in which 1 means very difficult to donand 5 means very easy to don. The gloves had a donning rating of 4.5which was similar to that of gloves coated with 100% polyisoprene(Sample 2A in Table 3).

Packed gloves were aged at 70° C. for 1 day and 7 days and evaluated forthe extent the internal surfaces of the gloves stuck to each other. Thedegree of stickiness was rated on a scale of 1 to 5 with 1 representingnot sticking at all and 5 representing seriously sticking to each other.The gloves did not stick to each other at all on the internal surfaceafter aging 1 day at 70° C. as well as after aging 7 days at 70° C. Theinternal stickiness ratings were 1 for both aging conditions. Theseresults were similar to those of gloves coated with 100% polyisoprene(Sample 2A in Table 5).

The adhesion of the alternate polyisoprene coating to the rubbersubstrate was evaluated. The finger and palm areas of the glove werestretched to about 500% and the coated surface was repeatedly rubbedusing the thumb. The coated surface was then visually examined forcoating flakes and powdery substance. The adhesion of the coating wasrated qualitatively on a scale of 1 to 5, 1 being the worst case withthe entire coating flaking off the rubber substrate and 5 being the bestcase with no sign of flaking and no visual appearance of powderysubstance on the surface of the glove. The adhesion of the alternatepolyisoprene coating was excellent with a rating of 5 (i.e. no flakingor shredding of powder was observed after stretching the glove to 500%and rubbing it repeatedly with the thumb). The adhesion of the alternatepolyisoprene coating is similar to that of the 100% polyisoprene coating(see Section 6.5).

TABLE 7 Alternate Polyisoprene coating formulation Ingredients phrKraton IR-401 RP PI latex 100 Soft water to dilute latex Sodiumcaseinate 0.75 Zinc Oxide Dispersion 0.5 Sulfur Dispersion 1.5 ZDBCDispersion 1 Wingstay L 2 Ammonium Hydroxide for adjusting pH > 10.2

6.10 Example 11 Natural Rubber Gloves with a Polyisoprene Blend Coating

Natural rubber gloves with a coating comprising a blend of 90%polyisoprene (PI) and 10% nitrile were prepared in the laboratoryaccording to the procedure described in Section 6.1. The coatingcomposition is given in Table 7 and is similar to the coatingcomposition that was given in Table 1 except that the Kraton IR-401 RPpolyisoprene latex was replaced by a blend comprising 90% polyisopreneand 10% Reichhold nitrile 68077-01 latex. The specific gravity of thecalcium nitrate coagulant was 1.150 and the NR latex total solidscontent was 47.5%. The total solids content of the polyisoprene/nitrileblend coating composition was 8%. The gloves were coated with apolyisoprene/nitrile coating after leaching of the NR latex film. Thegloves were cured for 30 minutes at 135° C. The gloves produced had afinger thickness of 0.31 mm. The formed gloves were chlorinated at 420ppm according to the procedure described in Section 6.1. Afterchlorination, the gloves were dried, packed and evaluated.

Gloves were donned on dry hands and subjectively assessed for the easeof donning on a scale of 1 to 5, in which 1 means very difficult to donand 5 means very easy to don. The gloves had a donning rating of 4.5which was similar to that of gloves coated with 100% polyisoprene(Sample 2A in Table 3).

Packed gloves were aged at 70° C. for 1 day and 7 days and evaluated forthe extent the internal surfaces of the gloves stuck to each other. Thedegree of stickiness was rated on a scale of 1 to 5 with 1 representingnot sticking at all and 5 representing seriously sticking to each other.The gloves were not sticking to each other at all on the internalsurface after aging 1 day at 70° C. as well as after aging 7 days at 70°C. The internal stickiness ratings were 1 for both aging conditions.These results were similar to those of gloves coated with 100%polyisoprene (Sample 2A in Table 5).

The adhesion of the inventive polyisoprene/nitrile blend coating to therubber substrate was evaluated. The finger and palm areas of the glovewere stretched to about 500% and the coated surface was repeatedlyrubbed using the thumb. The coated surface was then visually examinedfor coating flakes and powdery substance. The adhesion of the coatingwas rated qualitatively on a scale of 1 to 5, 1 being the worst casewith the entire coating flaking off the rubber substrate and 5 being thebest case with no sign of flaking and no visual appearance of powderysubstance on the surface of the glove. The adhesion of the inventivepolyisoprene/nitrile blend coating was excellent with a rating of 5 i.e.no flaking or shredding of powder was observed after stretching theglove to 500% and rubbing it repeatedly with the thumb. The adhesion ofthe polyisoprene/nitrile coating is similar to that of 100% polyisoprenecoating (see Section 6, 5 or 6.10).

TABLE 8 Polyisoprene/nitrile coating formulation Ingredients phr KratonIR-401 RP PI latex 90 Reichhold Nitrile 68077-01 10 Soft water to dilutelatex Sodium caseinate 0.75 Zinc Oxide Dispersion 0.5 Sulfur Dispersion1.25 Bostex 561 (ZDEC) 0.5 ZMBT dispersion 0.5 Bostex 417 (DPG) 1Wingstay L 2 Ammonium Hydroxide for adjusting pH > 10.2

INDUSTRIAL APPLICABILITY

The invention is useful in a manufacturing process for elastomericarticles composed of natural rubber, synthetic polyisoprene, syntheticpolymers such as neoprene, polyurethane, nitrile, vinyl, styrenebutadiene and co-polymer of butadiene. The invention affords the abilityto produce the elastomeric articles with a polyisoprene coating wherebythe coated surfaces have no or reduced stickiness/tackiness and improvedlubricity. The invention can be advantageously incorporated into themanufacturing of surgical gloves, condoms, probe covers, dental dams,finger cots, catheters, and the like.

The invention has been described with reference to various specific andpreferred embodiments and techniques. However, it should be understoodthat many variations and modifications can be made while remainingwithin the spirit or scope of the invention as defined by the claims setforth below.

What is claimed is:
 1. A method of coating an elastomeric rubber articlecomprising: providing an elastomeric rubber article comprising a layerof elastomer selected from the group consisting of syntheticpolyisoprene, polychloroprene, nitrile, carboxylated acrylonitrilebutadiene rubber, styrene butadiene rubber, butadiene co-polymer,polyurethane, vinyl, and mixtures thereof; and coating the elastomericrubber article on at least a portion of at least one elastomeric surfacewith a synthetic polyisoprene rubber coating composition to form asynthetic polyisoprene rubber coating on the at least one elastomericsurface of the elastomeric rubber article, wherein the syntheticpolyisoprene coating composition further comprises a crosslinking agentcomprising sulfur and a sulfur donor selected from the group consistingof tetramethyl thiuram disulfide (TMTD) and tetraethyl thiuram disulfide(TETD); wherein the coating comprising the synthetic polyisoprene rubberhas protrusions made of the synthetic polyisoprene rubber and whereinthe protrusions are in the range of 0.5 microns to 10 microns, andwherein the coated elastomeric rubber article exhibits an enhancedcharacteristic selected from the group consisting of improved dry skinlubricity, improved damp skin lubricity, decreased internal stickiness,increased comfort, increased softness, decreased skin irritation,decreased cracking of at least one of the elastomeric surface and thecoating on the elastomeric surface when stretched, and decreased flakingof at least one of the elastomeric surface and the coating on theelastomeric surface when stretched, as compared to an elastomeric rubberarticle that comprises the same layer of elastomer as the coatedelastomeric rubber article, but is not coated with a syntheticpolyisoprene rubber coating.
 2. The method of claim 1 wherein theelastomeric rubber article not coated with synthetic polyisoprene rubberis selected from the group consisting of a noncoated elastomericarticle, an acrylic coated elastomeric article, and a hydrogel coatedelastomeric article.
 3. The method of claim 1 wherein the syntheticpolyisoprene rubber coating further comprises an elastomer selected fromthe group consisting of natural rubber, polychloroprene, nitrile,carboxylated acrylonitrile butadiene rubber, styrene butadiene,butadiene co-polymer, polyurethane and polyvinyl chloride.
 4. The methodof claim 1 wherein the elastomeric rubber article having a coating ofsynthetic polyisoprene rubber is chlorinated.
 5. The method of claim 1wherein the coating comprising the synthetic polyisoprene rubber has athickness in the range of from about 1 micron to about 20 microns. 6.The method of claim 1 wherein the elastomeric rubber article beingcoated is selected from the group consisting of a medical glove, medicaltube, condoms, probe cover, dental dam, finger cot, film, shunt, valve,stent, and implant.
 7. The method of claim 1 wherein the syntheticpolyisoprene coating composition has a total solids content of fromabout 0.5 to about 15%.
 8. The method of claim 1 wherein the syntheticpolyisoprene coating composition has a total solids content of fromabout 5 to about 8%.
 9. The method of claim 1 wherein the syntheticpolyisoprene coating composition further comprises an acceleratorcomposition selected from the group consisting of zincdibutyldithiocarbamate (ZDBC), zinc diethyldithiocarbamate (ZDEC), zincmercaptobenzthiazole (ZMBT), and diphenyl guanidine (DPG).
 10. Themethod of claim 1 wherein the synthetic polyisoprene coating compositionfurther comprises an antioxidant selected from the group consisting of

and


11. The method of claim 1 wherein the synthetic polyisoprene rubbercoating composition comprises an activator selected from the groupconsisting of zinc oxide and magnesium oxide.
 12. The method of claim 1wherein the synthetic polyisoprene rubber coating of the coatedelastomeric rubber article is treated with a lubricant solution.
 13. Amethod of coating an elastomeric rubber article comprising: providing anelastomeric rubber article comprising a layer of elastomer selected fromthe group consisting of synthetic polyisoprene, polychloroprene,nitrile, carboxylated acrylonitrile butadiene rubber, styrene butadienerubber, butadiene co-polymer, polyurethane, vinyl, and mixtures thereof;coating the elastomeric rubber article on at least a portion of at leastone elastomeric surface with a synthetic polyisoprene rubber coatingcomposition to form a synthetic polyisoprene rubber coating on theelastomeric surface of the elastomeric rubber article; and chlorinatingthe coated elastomeric rubber article, wherein the coating comprisingthe synthetic polyisoprene rubber has protrusions made of the syntheticpolyisoprene rubber and wherein the protrusions are in the range of 0.5microns to 10 microns, and wherein the coated elastomeric rubber articleexhibits an enhanced characteristic selected from the group consistingof improved dry skin lubricity, improved damp skin lubricity, decreasedinternal stickiness, increased comfort, increased softness, decreasedskin irritation, decreased cracking of at least one of the elastomericsurface and the coating on the elastomeric surface, and decreasedflaking of at least one of the elastomeric surface and the coating onthe elastomeric surface when stretched, as compared to an elastomericrubber article that comprises the same layer of elastomer as the coatedelastomeric rubber article, but is not coated with a syntheticpolyisoprene rubber coating.
 14. The method of claim 13 wherein theelastomeric rubber article not coated with synthetic polyisoprene rubberis selected from the group consisting of a noncoated elastomericarticle, an acrylic coated elastomeric article, and a hydrogel coatedelastomeric article.
 15. The method of claim 13 wherein the syntheticpolyisoprene rubber coating further comprises an elastomer selected fromthe group consisting of natural rubber, polychloroprene, nitrile,carboxylated acrylonitrile butadiene rubber, styrene butadiene,butadiene co-polymer, polyurethane and polyvinyl chloride.
 16. Themethod of claim 13 wherein the coating of synthetic polyisoprene rubberis treated with a lubricant solution.
 17. The method of claim 13 whereinthe coating comprising the synthetic polyisoprene rubber has a thicknessin the range of from about 1 micron to about 20 microns.
 18. The methodof claim 13 wherein the elastomeric rubber article being coated isselected from the group consisting of a medical glove, medical tube,condoms, probe cover, dental dam, finger cot, film, shunt, valve, stent,and implant.
 19. The method of claim 13 wherein the syntheticpolyisoprene coating composition has a total solids content of fromabout 0.5 to about 15%.
 20. The method of claim 13 wherein the syntheticpolyisoprene coating composition has a total solids content of fromabout 5 to about 8%.
 21. The method of claim 13 wherein the syntheticpolyisoprene coating composition further comprises a crosslinking agentcomprising sulfur and a sulfur donor selected from the group consistingof tetramethyl thiuram disulfide (TMTD) and tetraethyl thiuram disulfide(TETD).
 22. The method of claim 13 wherein the synthetic polyisoprenecoating composition further comprises an accelerator compositionselected from the group consisting of zinc dibutyldithiocarbamate(ZDBC), zinc diethyldithiocarbamate (ZDEC), zinc mercaptobenzthiazole(ZMBT), and diphenyl guanidine (DPG).
 23. The method of claim 13 whereinthe synthetic polyisoprene coating composition further comprises anantioxidant selected from the group consisting of

and


24. The method of claim 13 wherein the synthetic polyisoprene rubbercoating composition comprises an activator selected from the groupconsisting of zinc oxide and magnesium oxide.
 25. A method of coating anelastomeric rubber article comprising: providing an elastomeric rubberarticle comprising a layer of elastomer selected from the groupconsisting of synthetic polyisoprene, polychloroprene, nitrile,carboxylated acrylonitrile butadiene rubber, styrene butadiene rubber,butadiene co-polymer, polyurethane, vinyl, and mixtures thereof; andcoating the elastomeric rubber article on at least a portion of at leastone elastomeric surface with a synthetic polyisoprene rubber coatingcomposition to form a synthetic polyisoprene rubber coating on theelastomeric surface of the elastomeric rubber article, wherein thecoating comprising the synthetic polyisoprene rubber has protrusionsmade of the synthetic polyisoprene rubber and wherein the protrusionsare in the range of 0.5 microns to 10 microns in size, wherein thecoated elastomeric rubber article exhibits an enhanced characteristicselected from the group consisting of improved dry skin lubricity,improved damp skin lubricity, decreased internal stickiness, increasedcomfort, increased softness, decreased skin irritation, decreasedcracking of at least one of the elastomeric surface and the coating onthe elastomeric surface, and decreased flaking of at least one of theelastomeric surface and the coating on the elastomeric surface whenstretched, as compared to an elastomeric rubber article that comprisesthe same layer of elastomer as the coated elastomeric rubber article,but is not coated with a synthetic polyisoprene rubber coating.
 26. Themethod of claim 24 wherein the elastomeric rubber article not coatedwith synthetic polyisoprene rubber is selected from the group consistingof a noncoated elastomeric article, an acrylic coated elastomericarticle, and a hydrogel coated elastomeric article.
 27. The method ofclaim 25 wherein the synthetic polyisoprene rubber coating furthercomprises an elastomer selected from the group consisting of naturalrubber, polychloroprene, nitrile, carboxylated acrylonitrile butadienerubber, styrene butadiene, butadiene co-polymer, polyurethane andpolyvinyl chloride.
 28. The method of claim 25 wherein the coating ofsynthetic polyisoprene rubber is treated with a lubricant solution. 29.The method of claim 25 wherein the elastomeric rubber article having acoating of synthetic polyisoprene rubber is chlorinated.
 30. The methodof claim 25 wherein the coating comprising the synthetic polyisoprenerubber has a thickness in the range of from about 1 micron to about 20microns.
 31. The method of claim 25 wherein the elastomeric rubberarticle being coated is selected from the group consisting of a medicalglove, medical tube, condoms, probe cover, dental dam, finger cot, film,shunt, valve, stent, and implant.
 32. The method of claim 25 wherein thesynthetic polyisoprene coating composition has a total solids content offrom about 0.5 to about 15%.
 33. The method of claim 25 wherein thesynthetic polyisoprene coating composition has a total solids content offrom about 5 to about 8%.
 34. The method of claim 25 wherein thesynthetic polyisoprene coating composition further comprises acrosslinking agent comprising sulfur and a sulfur donor selected fromthe group consisting of tetramethyl thiuram disulfide (TMTD) andtetraethyl thiuram disulfide (TETD).
 35. The method of claim 25 whereinthe synthetic polyisoprene coating composition further comprises anaccelerator composition selected from the group consisting of zincdibutyldithiocarbamate (ZDBC), zinc diethyldithiocarbamate (ZDEC), zincmercaptobenzthiazole (ZMBT), and diphenyl guanidine (DPG).
 36. Themethod of claim 25 wherein the synthetic polyisoprene coatingcomposition further comprises an antioxidant selected from the groupconsisting of

and


37. The method of claim 25 wherein the synthetic polyisoprene rubbercoating composition comprises an activator selected from the groupconsisting of zinc oxide and magnesium oxide.
 38. A method of coating anelastomeric rubber article comprising: providing an elastomeric rubberarticle comprising a layer of elastomer selected from the groupconsisting of synthetic polyisoprene, polychloroprene, nitrile,carboxylated acrylonitrile butadiene rubber, styrene butadiene rubber,butadiene co-polymer, polyurethane, vinyl, and mixtures thereof; andcoating the elastomeric rubber article on at least a portion of at leastone elastomeric surface with a synthetic polyisoprene rubber coatingcomposition to form a synthetic polyisoprene rubber coating on theelastomeric surface of the elastomeric rubber article, wherein thesynthetic polyisoprene coating composition further comprises anaccelerator composition selected from the group consisting of zincdibutyldithiocarbamate (ZDBC), zinc diethyldithiocarbamate (ZDEC), zincmercaptobenzthiazole (ZMBT), and diphenyl guanidine (DPG); wherein thecoating comprising the synthetic polyisoprene rubber has protrusionsmade of the synthetic polyisoprene rubber and wherein the protrusionsare in the range of 0.5 microns to 10 microns, and wherein the coatedelastomeric rubber article exhibits an enhanced characteristic selectedfrom the group consisting of improved dry skin lubricity, improved dampskin lubricity, decreased internal stickiness, increased comfort,increased softness, decreased skin irritation, decreased cracking of atleast one of the elastomeric surface and the coating on the elastomericsurface, and decreased flaking of at least one of the elastomericsurface and the coating on the elastomeric surface when stretched, ascompared to an elastomeric rubber article that comprises the same layerof elastomer as the coated elastomeric rubber article, but is not coatedwith a synthetic polyisoprene rubber coating.
 39. The method of claim 38wherein the elastomeric rubber article not coated with syntheticpolyisoprene rubber is selected from the group consisting of a noncoatedelastomeric article, an acrylic coated elastomeric article, and ahydrogel coated elastomeric article.
 40. The method of claim 38 whereinthe synthetic polyisoprene rubber coating further comprises an elastomerselected from the group consisting of natural rubber, polychloroprene,nitrile, carboxylated acrylonitrile butadiene rubber, styrene butadiene,butadiene co-polymer, polyurethane and polyvinyl chloride.
 41. Themethod of claim 38 wherein the elastomeric rubber article having acoating of synthetic polyisoprene rubber is chlorinated.
 42. The methodof claim 38 wherein the coating comprising the synthetic polyisoprenerubber has a thickness in the range of from about 1 micron to about 20microns.
 43. The method of claim 38 wherein the elastomeric rubberarticle being coated is selected from the group consisting of a medicalglove, medical tube, condoms, probe cover, dental dam, finger cot, film,shunt, valve, stent, and implant.
 44. The method of claim 38 wherein thesynthetic polyisoprene coating composition has a total solids content offrom about 0.5 to about 15%.
 45. The method of claim 38 wherein thesynthetic polyisoprene coating composition has a total solids content offrom about 5 to about 8%.
 46. The method of claim 38 wherein thesynthetic polyisoprene coating composition further comprises acrosslinking agent comprising sulfur and a sulfur donor selected fromthe group consisting of tetramethyl thiuram disulfide (TMTD) andtetraethyl thiuram disulfide (TETD).
 47. The method of claim 38 whereinthe synthetic polyisoprene coating composition further comprises anantioxidant selected from the group consisting of

and


48. The method of claim 38 wherein the synthetic polyisoprene rubbercoating composition comprises an activator selected from the groupconsisting of zinc oxide and magnesium oxide.
 49. The method of claim 38wherein the synthetic polyisoprene rubber coating of the coatedelastomeric rubber article is treated with a lubricant solution.
 50. Amethod of coating an elastomeric rubber article comprising: providing anelastomeric rubber article comprising a layer of elastomer selected fromthe group consisting of synthetic polyisoprene, polychloroprene,nitrile, carboxylated acrylonitrile butadiene rubber, styrene butadienerubber, butadiene co-polymer, polyurethane, vinyl, and mixtures thereof;and coating the elastomeric rubber article on at least a portion of atleast one elastomeric surface with a synthetic polyisoprene rubbercoating composition to form a synthetic polyisoprene rubber coating onthe elastomeric surface of the elastomeric rubber article, wherein thesynthetic polyisoprene coating composition further comprises anantioxidant selected from the group consisting of

and

wherein the coating comprising the synthetic polyisoprene rubber hasprotrusions made of the synthetic polyisoprene rubber and wherein theprotrusions are in the range of 0.5 microns to 10 microns, and whereinthe coated elastomeric rubber article exhibits an enhancedcharacteristic selected from the group consisting of improved dry skinlubricity, improved damp skin lubricity, decreased internal stickiness,increased comfort, increased softness, decreased skin irritation,decreased cracking of at least one of the elastomeric surface and thecoating on the elastomeric surface, and decreased flaking of at leastone of the elastomeric surface and the coating on the elastomericsurface when stretched, as compared to an elastomeric rubber articlethat comprises the same layer of elastomer as the coated elastomericrubber article, but is not coated with a synthetic polyisoprene rubbercoating.
 51. The method of claim 50 wherein the elastomeric rubberarticle not coated with synthetic polyisoprene rubber is selected fromthe group consisting of a noncoated elastomeric article, an acryliccoated elastomeric article, and a hydrogel coated elastomeric article.52. The method of claim 50 wherein the synthetic polyisoprene rubbercoating further comprises an elastomer selected from the groupconsisting of natural rubber, polychloroprene, nitrile, carboxylatedacrylonitrile butadiene rubber, styrene butadiene, butadiene co-polymer,polyurethane and polyvinyl chloride.
 53. The method of claim 50 whereinthe elastomeric rubber article having a coating of syntheticpolyisoprene rubber is chlorinated.
 54. The method of claim 50 whereinthe coating comprising the synthetic polyisoprene rubber has a thicknessin the range of from about 1 micron to about 20 microns.
 55. The methodof claim 50 wherein the elastomeric rubber article being coated isselected from the group consisting of a medical glove, medical tube,condoms, probe cover, dental dam, finger cot, film, shunt, valve, stent,and implant.
 56. The method of claim 50 wherein the syntheticpolyisoprene coating composition has a total solids content of fromabout 0.5 to about 15%.
 57. The method of claim 50 wherein the syntheticpolyisoprene coating composition has a total solids content of fromabout 5 to about 8%.
 58. The method of claim 50 wherein the syntheticpolyisoprene coating composition further comprises a crosslinking agentcomprising sulfur and a sulfur donor selected from the group consistingof tetramethyl thiuram disulfide (TMTD) and tetraethyl thiuram disulfide(TETD).
 59. The method of claim 50 wherein the synthetic polyisoprenecoating composition further comprises an accelerator compositionselected from the group consisting of zinc dibutyldithiocarbamate(ZDBC), zinc diethyldithiocarbamate (ZDEC), zinc mercaptobenzthiazole(ZMBT), and diphenyl guanidine (DPG).
 60. The method of claim 50 whereinthe synthetic polyisoprene rubber coating composition comprises anactivator selected from the group consisting of zinc oxide and magnesiumoxide.
 61. A method of coating an elastomeric rubber article comprising:providing an elastomeric rubber article comprising a layer of elastomerselected from the group consisting of synthetic polyisoprene,polychloroprene, nitrile, carboxylated acrylonitrile butadiene rubber,styrene butadiene rubber, butadiene co-polymer, polyurethane, vinyl, andmixtures thereof; and coating the elastomeric rubber article on at leasta portion of at least one elastomeric surface with a syntheticpolyisoprene rubber coating composition to form a synthetic polyisoprenerubber coating on the elastomeric surface of the elastomeric rubberarticle, wherein the synthetic polyisoprene rubber coating compositioncomprises an activator selected from the group consisting of zinc oxideand magnesium oxide; wherein the coating comprising the syntheticpolyisoprene rubber has protrusions made of the synthetic polyisoprenerubber and wherein the protrusions are in the range of 0.5 microns to 10microns, and wherein the coated elastomeric rubber article exhibits anenhanced characteristic selected from the group consisting of improveddry skin lubricity, improved damp skin lubricity, decreased internalstickiness, increased comfort, increased softness, decreased skinirritation, decreased cracking of at least one of the elastomericsurface and the coating on the elastomeric surface, and decreasedflaking of at least one of the elastomeric surface and the coating onthe elastomeric surface when stretched, as compared to an elastomericrubber article that comprises the same layer of elastomer as the coatedelastomeric rubber article, but is not coated with a syntheticpolyisoprene rubber coating.
 62. The method of claim 61 wherein theelastomeric rubber article not coated with synthetic polyisoprene rubberis selected from the group consisting of a noncoated elastomericarticle, an acrylic coated elastomeric article, and a hydrogel coatedelastomeric article.
 63. The method of claim 61 wherein the syntheticpolyisoprene rubber coating further comprises an elastomer selected fromthe group consisting of natural rubber, polychloroprene, nitrile,carboxylated acrylonitrile butadiene rubber, styrene butadiene,butadiene co-polymer, polyurethane and polyvinyl chloride.
 64. Themethod of claim 61 wherein the elastomeric rubber article having acoating of synthetic polyisoprene rubber is chlorinated.
 65. The methodof claim 61 wherein the coating comprising the synthetic polyisoprenerubber has a thickness in the range of from about 1 micron to about 20microns.
 66. The method of claim 61 wherein the elastomeric rubberarticle being coated is selected from the group consisting of a medicalglove, medical tube, condoms, probe cover, dental dam, finger cot, film,shunt, valve, stent, and implant.
 67. The method of claim 61 wherein thesynthetic polyisoprene coating composition has a total solids content offrom about 0.5 to about 15%.
 68. The method of claim 61 wherein thesynthetic polyisoprene coating composition has a total solids content offrom about 5 to about 8%.
 69. The method of claim 61 wherein thesynthetic polyisoprene coating composition further comprises acrosslinking agent comprising sulfur and a sulfur donor selected fromthe group consisting of tetramethyl thiuram disulfide (TMTD) andtetraethyl thiuram disulfide (TETD).
 70. The method of claim 61 whereinthe synthetic polyisoprene coating composition further comprises anaccelerator composition selected from the group consisting of zincdibutyldithiocarbamate (ZDBC), zinc diethyldithiocarbamate (ZDEC), zincmercaptobenzthiazole (ZMBT), and diphenyl guanidine (DPG).
 71. Themethod of claim 61 wherein the synthetic polyisoprene coatingcomposition further comprises an antioxidant selected from the groupconsisting of

and


72. The method of claim 61 wherein the synthetic polyisoprene rubbercoating of the coated elastomeric rubber article is treated with alubricant solution.
 73. A method of coating an elastomeric rubberarticle comprising: providing an elastomeric rubber article comprising alayer of elastomer selected from the group consisting of syntheticpolyisoprene, polychloroprene, nitrile, carboxylated acrylonitrilebutadiene rubber, styrene butadiene rubber, butadiene co-polymer,polyurethane, vinyl, and mixtures thereof; and coating the elastomericrubber article on at least a portion of at least one elastomeric surfacewith a synthetic polyisoprene rubber coating composition to form asynthetic polyisoprene rubber surface coating on the elastomeric surfaceof the elastomeric rubber article, wherein the synthetic polyisoprenecoating composition further comprises an antioxidant selected from thegroup consisting of

and

wherein the coating comprising the synthetic polyisoprene rubber hasprotrusions made of the synthetic polyisoprene rubber and wherein theprotrusions are in the range of 0.5 microns to 10 microns, wherein thesynthetic polyisoprene rubber coating of the coated elastomeric rubberarticle is treated with a lubricant solution, and wherein the coatedelastomeric rubber article exhibits an enhanced characteristic selectedfrom the group consisting of improved dry skin lubricity, improved dampskin lubricity, decreased internal stickiness, increased comfort,increased softness, decreased skin irritation, decreased cracking of atleast one of the elastomeric surface and the coating on the elastomericsurface, and decreased flaking of at least one of the elastomericsurface and the coating on the elastomeric surface when stretched, ascompared to an elastomeric rubber article that comprises the same layerof elastomer as the coated elastomeric rubber article, but is not coatedwith a synthetic polyisoprene rubber coating.
 74. The method of claim 50wherein the synthetic polyisoprene rubber coating of the coatedelastomeric rubber article is treated with a lubricant solution.
 75. Themethod of claim 1, wherein the step of coating the elastomeric rubberarticle comprises a process selected from the group consisting ofdipping, spraying, brushing, flowing, and printing.
 76. The method ofclaim 13, wherein the step of coating the elastomeric rubber articlecomprises a process selected from the group consisting of dipping,spraying, brushing, flowing, and printing.
 77. The method of claim 25,wherein the step of coating the elastomeric rubber article comprises aprocess selected from the group consisting of dipping, spraying,brushing, flowing, and printing.
 78. The method of claim 38, wherein thestep of coating the elastomeric rubber article comprises a processselected from the group consisting of dipping, spraying, brushing,flowing, and printing.
 79. The method of claim 50, wherein the step ofcoating the elastomeric rubber article comprises a process selected fromthe group consisting of dipping, spraying, brushing, flowing, andprinting.
 80. The method of claim 61, wherein the step of coating theelastomeric rubber article comprises a process selected from the groupconsisting of dipping, spraying, brushing, flowing, and printing. 81.The method of claim 73, wherein the step of coating the elastomericrubber article comprises a process selected from the group consisting ofdipping, spraying, brushing, flowing, and printing.